PS + CSOM to iterate webs, starting from the ClientContext web..

IterateWebs.ps1

. .\TopOfScript.ps1

$rootWeb = $clientContext.Web
$childWebs = $rootWeb.Webs
$clientContext.Load($rootWeb)
$clientContext.Load($childWebs)
$clientContext.ExecuteQuery()

function processWeb($web)
{
    $lists = $web.Lists
    $clientContext.Load($web)
    $clientContext.ExecuteQuery()
    Write-Host "Web URL is" $web.Url
}

foreach ($childWeb in $childWebs)
{
    processWeb($childWeb)
}